TAMPA The Tampa Bay Buccaneers have spent five years patiently tending to the development of right tackle Demar Dotson. Now it appears they believe their starter for the last 15 games of last year has developed into a keeper.

A former basketball player who didn’t start playing football until he became a defensive lineman during his senior year at Southern Mississippi, Dotson has signed a four-year, $4.5 million contract extension, the Bucs said.

The deal runs through 2016 and calls for Dotson’s projected 2013 salary of $2 million to be spit into a $1 million salary and $1 million roster bonus, and for Dotson to receive base salaries of $1.25 million in 2014, $1.5 million in 2015 and $1.75 million in 2016.

The deal marks the second time in the last year that the Bucs have extended Dotson’s contract, having signed him last March to a two-year, $2.5 million extension that included a $200,000 roster bonus.

The 6-foot-9, 315-pound Dotson first came to the Bucs as an undrafted free agent in 2009. He was immediately moved to offensive tackle and has steadily gained playing time since, emerging as the Bucs starter after Week One of last year.

“He brings incredible work ethic and focus and commitment to get better,’’ Bucs coach Greg Schiano said of Dotson during the recent NFL owners meetings. “And when you get those two (Pro Bowl) guards back (Carl Nicks and Davin Joseph) back, that makes his life better, too.’’

Dotson is considered to be a better pass blocker than run stopper and was part of a line last year that, even without Joseph and Nicks, allowed the third fewest sacks in the NFL (24).

That unit also helped quarterback Josh Freeman set single season team records for passing yards (4,065) and passing touchdowns (27) and helped Pro Bowl running back Doug Martin run for the second-most rushing yards (1,454) and touchdowns (11) in franchise history.